MANILA, Philippines -- The National Bureau of Investigation is looking into the alleged involvement of some Philippine National Police personnel in gun-running activities.

At least two NBI officials, who both asked not to be identified by name, told the Philippine Daily Inquirer that a utility worker at the PNP headquarters in Camp Crame was arrested by a composite team drawn from the NBI National Capital Region, the PNP Criminal Investigation and Detection Group, and the Intelligence Service of the Armed Forces of the Philippines during a buy-bust operation last week.

Seized from the suspect was a cache of firearms, including pistols and high-powered guns.

During interrogation, the suspect implicated four other people, including an active PNP officer and two non-uniformed personnel, all reportedly assigned at the Logistics Support Service of the PNP, and a gunsmith as among those involved in the gun-running activities.

The five were charged with violating Presidential Decree 1866 as amended by Republic Act 8294 (illegal manufacture, possession, distribution, and sale of firearms and ammunition), the sources said.

Investigation showed that the suspects' modus operandi involved selling guns that were "unserviceable," or those that were supposedly intended for repair. Many of the firearms came from the PNP's regional offices.

"Instead of having these guns undergo repair, these are being smuggled from the PNP headquarters for selling," one source added. "Documents na lang ang nakakarating sa Crame, wala na yung mga baril (It’s only the documents that get to Crame, the guns disappear."

Asked about reports that the firearms were being sold to rebels, like the New People's Army and the Moro Islamic Liberation Front, the other bureau official said: "That's the speculation, but so far, we haven't verified that information. What we gathered was that these firearms were illegally distributed but not particularly to rebels or any government insurgents."